On Jan 6 (with 2 little kids) we flew into EWR from LGW. Made it through immigration, baggage claim, customs, baggage recheck, and security the fastest I've ever been able to do so - 53 minutes from arriving airplane to door of departing airplane. Of course, this was all in the same terminal, C, security line was nearly empty, and we knew where we were going. The biggest bottleneck was baggage claim in which our suitcases arrived about 30 minutes after we landed. So, you have about 22 minutes of padding. Good luck!